We're looking to buy a printer for a mobile cart that we use once per week. The problem is the cart is stored in a trailer outside and in the winter (in Wisconsin) it gets very cold.

If we get an ink jet printer, I'm wondering if the printer or ink would be damaged by freezing and thawing and freezing over and over. Also wondering how long it might take to thaw out if it comes in from a 10 degree day into a standard building.

Same questions with toner. I'm assuming toner would be better since it's not a liquid but I still don't know if it's affected by being in possible sub-zero temperatures.

Modelworks is right. Ink will freeze but at what temperature depends on the ink's composition.
For a typical (home/office) inkjet printer (using aqueous-based ink), the ink consists of: 2-8 weight % colourant (dye or pigment), 2-5% surfactants and additives, i.e., glycerine, 10-30% humectant, i.e., EG, DEG, 2-propanol, diethanolamine, and water. So the freezing point of inks can vary with their humecant concentration.

The colourants in an inkjet ink are either dye based or pigment based: a dye is a colourant that is fully dissolved in the carrier fluid; a pigment is a fine powder of solid colourants particles dispersed in the carrier fluid. That's why inkjet cartridges have a typical self life of 1 to 2 years. The pigment particles will start to settle or separate.

MSDS of inks from HP, Canon, or Epson do not list freezing points. Epson's MSDS state <32F. Not very helpful.

It's a bad idea to store your inkjet printer cartridges in an outside trailer, especially in Wisconsin. The cartridges may crack due to ink expansion when they freeze; and the pigment particles will also separate when the ink freezes and may not re-emulsify when it thaws.

Regularly exposing printers to temperature extremes is not a good idea. This would not only include issues with ink & toner cartridges, but also printer components such as laser fusers, motors, belts and even circuit board components using electrolytic capacitors. There also is the issue of moisture accumulation on/in items undergoing thawing. Also, printers may use composite rubber belts which become stiff under low temperatures.

On ink jet printing systems, although the freezing point of the ink will be lower than that of pure water, the difference is SMALL - probably no more than 5 degrees. So in Wisconsin in winter, this is NOT any help at all! Assume the ink WILL freeze when the printer is exposed to outside winter temps.

Freezing of the ink can cause two types of problems. The obvious one is that the ink expands (as water does) when frozen, and hence can break containers. The other is that some ink formulations may be de-stabilized by a freeze / thaw process so that components clump up into tiny solid slush that blocks the fine tubing in the printer and the head nozzles. These problems are NOT isolated to the ink cartridges themselves, so keeping the cartridges only warm does not solve the problem. The ink tubing and the print head also will experience all the same problems with the small volumes of ink they contain. Bottom line is: DO NOT FREEZE any inkjet printer!

Comments by others on the general effects of cold on all printer parts, not even thinking of inks and toners, are right. Even if you were to bring the cold printer inside and let it warm up and then dry out (condensate) for a while, it's risky. But the real problem is: define "for a while". At a GUESS for a closed printer sitting in a warm room, I'd say it might be safe in 24 hours, and that may be quite wrong - either too long or too short - I'm not sure. It is certainly more than a couple of hours! So the risk is not worth it for ANY printer!

For what its worth, I googled the laser printer question, and at least Epson and HP agreed at a 50 F =10 C minimum operating temp.

But question to OP, would a dot impact printer do the trailer printing job needed?
Or alternately the print job could be stored on USB pen drives or other storage media and taken to a warmer location to complete the printing job.

This is something that we'd use at church on Sundays. We store the supplies in an off-site trailer and just bring them into the location Sunday morning. We sometimes realize we forgot to print something and instead of driving 10 minutes back to the office, it'd be nice to have a mobile printer.

We might just have someone bring it from the office in the morning but thought we wouldn't forget it we just kept it with the supplies.